return element occured more than n/3 times

int Solution::repeatedNumber(const vector<int> &A) {

    int n=A.size();
    n/=3;
    map<int,int> m;
    for(auto x:A)
    {
        m[x]++;
        if(m[x]>n)
        return x;
    }

    return -1;

}